Xylose Testing Test
A xylose test checks how well your intestines absorb a type of sugar called xylose. It helps diagnose problems with absorbing nutrients from food.
What this test measures
Xylose testing measures the level of xylose in your blood and urine to see how well your intestines absorb carbohydrates.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
High levels of xylose are normal. It means that your intestines are absorbing the xylose. If your results are high, that may mean that your symptoms are not caused by malabsorption.
Lower-than-normal results
Lower-than-normal levels of xylose in the blood or urine may mean you have a malabsorption disorder, such as celiac disease, Crohn's disease, or Whipple disease. It may also be caused by an infection from a parasite like hookworm or giardiasis.
Frequently asked questions
What is a xylose test?
A xylose test checks the level of xylose in your blood and urine to see how well you absorb carbohydrates.
Why is a xylose test done?
It is most often used to help diagnose malabsorption disorders and to find out why a child is not gaining weight.
What does a high xylose level mean?
High levels are normal and mean your intestines are absorbing xylose well.
What does a low xylose level mean?
Low levels may mean you have a malabsorption disorder such as celiac disease, Crohn's disease, or Whipple disease, or an infection from a parasite.
Is the xylose test still commonly used?
No, xylose testing is no longer routinely ordered and may not be available everywhere.
Related lab tests
Sources
- MedlinePlus: Xylose Testing — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.